1. Field of the Invention
The present invention relates to a patch type of circularly polarized wave antenna device that is suitable for a GPS antenna or the like.
2. Description of the Related Art
FIG. 24 is a perspective view of a conventional circularly polarized wave antenna device. A configuration of the conventional circularly polarized wave antenna device will be described with reference to FIG. 24. A patterned ground conductor 52 is provided on a bottom surface of a thick dielectric substrate 51 made of an insulating material, and a patterned radiating conductor 53 is provided on a top surface of the dielectric substrate 51.
Further, the radiating conductor 53 is formed substantially in a square shape and has a feeding portion 54 protruding from one side thereof. In addition, circularly polarized cut portions 53a are respectively provided in two corner portions opposite to each other. In this manner, the conventional circularly polarized wave antenna device is formed (for example, see Japanese Unexamined Patent Application Publication No. 2002-237714).
However, in the conventional circularly polarized wave antenna device, the antenna efficiency is lowered due to the dielectric loss caused by the dielectric substrate 51. In addition, since the radiating conductor 53 has a rectangular shape, the overall size of the antenna device increases. As a result, it is difficult to realize a small-size antenna device.